STL容器使用案例文档

STL 容器文档

@author 鲁伟林之前常用的语言是: C++。现在使用的是Java，所以抽空整理下C++集合的使用方法。gitHub地址：https://github.com/thinkingfioa/Notes/blob/master/TechFiles/STL_Usage.md主要通过Demo下列容器用法 + 遍历算法:1. vector[push_back, pop_back, insert, erase, swap]2. set[insert, erase, swap, find, count]3. stack[top, push, pop, swap]4. queue[push, pop, swap, back, front]5. map[insert, erase, swap]6. deque[front, back, push_back, push_front, pop_back, pop_front, insert, erase, swap]7. Algorithm[find, copy, swap, count, replace, fill, reverse, merge, min, max]

vector

push_back

vector<int> myVector;myVector.push_back(100);

pop_back

从后往前pop

vector<int> myVector;myVector.push_back(100);myVector.push_back(200);myVector.push_back(300);//执行前: 100, 200, 300myVector.pop_back();//执行后: 100, 200

insert

#include <iostream>#include <vector>int main (){  std::vector<int> myvector (3,100);  std::vector<int>::iterator it;  //执行前: 100, 100, 100  it = myvector.begin();  it = myvector.insert ( it , 200 );  //执行后: 200, 100, 100, 100    //执行前: 200, 100, 100, 100  myvector.insert (it,2,300);  //执行后: 300, 300, 200, 100, 100, 100      // "it" no longer valid, get a new one:  it = myvector.begin();  //执行前: 300, 300, 200, 100, 100, 100  std::vector<int> anothervector (2,400);  myvector.insert (it+2,anothervector.begin(),anothervector.end());  //执行后: 300, 300, 400, 400, 200, 100, 100, 100  int myarray [] = { 501,502,503 };  //执行前: 300, 300, 400, 400, 200, 100, 100, 100  myvector.insert (myvector.begin(), myarray, myarray+3);  //执行后: 501, 502, 503, 300, 300, 400, 400, 200, 100, 100, 100  return 0;}

erase

vector<int> myVector;for(int i =0; i<10;i++) {    myVector.push_back(i);}//执行前: 1, 2, 3, 4, 5, 6, 7, 8, 9myVector.erase(myVector.begin() +5); // 移除下标为5的数,也就是myVector[5]=6//执行后: 1, 2, 3, 4, 5, 7, 8, 9//执行前: 1, 2, 3, 4, 5, 7, 8, 9myVector.erase(myVector.begin(), myVector.begin() + 3);//执行后: 4, 5, 7, 8, 9

swap

  std::vector<int> foo (3,100);   // three ints with a value of 100  std::vector<int> bar (5,200);   // five ints with a value of 200  //执行前: foo: [100, 100, 100]  //       bar: [200, 200, 200, 200, 200]  foo.swap(bar);  //执行后: foo: [200, 200, 200, 200, 200]  //       bar: [100, 100, 100]

遍历

迭代器遍历

for (it=myvector.begin(); it<myvector.end(); it++){    std::cout << ' ' << *it;}

set

C++中的Set是一个有序-去重集合

insert

  std::set<int> myset;  std::set<int>::iterator it;  std::pair<std::set<int>::iterator,bool> ret;  // set some initial values:  for (int i=1; i<=5; ++i) myset.insert(i*10);     //执行前: 10, 20, 30, 40, 50  ret = myset.insert(20);  // no new element inserted  //执行后: 10, 20, 30, 40, 50  if (ret.second==false) it=ret.first;  // "it" now points to element 20  //执行前: 10, 20, 30, 40, 50  myset.insert (it,25);                 // max efficiency inserting  myset.insert (it,24);                 // max efficiency inserting  myset.insert (it,26);                 // no max efficiency inserting  //执行后: 10, 20, 24, 25, 26, 30, 40, 50    //执行前: 10, 20, 24, 25, 26, 30, 40, 50  int myints[]= {5,10,15};              // 10 already in set, not inserted  myset.insert (myints,myints+3);  //执行后: 5, 10, 15, 20, 24, 25, 26, 30, 40, 50

erase

  std::set<int> myset;  std::set<int>::iterator it;  // insert some values:  for (int i=1; i<10; i++) myset.insert(i*10);  // 10 20 30 40 50 60 70 80 90  it = myset.begin();  ++it;                                         // "it" points now to 20  // 执行前: 10, 20, 30, 40, 50, 60, 70, 80, 90; //(*it) = 20  myset.erase (it);  //执行后: 10, 30, 40, 50, 60, 70, 80, 90;     //执行前: 10, 30, 40, 50, 60, 70, 80, 90;  myset.erase (40);  //执行后: 10, 30, 50, 60, 70, 80, 90;     it = myset.find (60);  //执行前: 10, 30, 50, 60, 70, 80, 90;   myset.erase (it, myset.end());  //执行后: 10, 30, 50;

swap

  int myints[]={12,75,10,32,20,25};  std::set<int> first (myints,myints+3);     // 10,12,75  std::set<int> second (myints+3,myints+6);  // 20,25,32  //执行前: first [10, 12, 75]  //        second [20, 25, 32]  first.swap(second);  //执行后: first [20, 25, 32]  //       second [10, 12, 75] 

find

  std::set<int> myset;  std::set<int>::iterator it;  // set some initial values:  for (int i=1; i<=5; i++) myset.insert(i*10);    // set: 10 20 30 40 50  // 执行前: 10, 20, 30, 40, 50  it=myset.find(20);  myset.erase (it);  // 执行后: 10, 30, 40, 50

count

由于set集合不重复，所以count(val)返回的结果只有0或者1.

  std::set<int> myset;  // set some initial values:  for (int i=1; i<5; ++i) myset.insert(i*3);    // set: 3 6 9 12  //返回结果是: 1  myset.count(3);  //返回结果是: 0  myset.count(5);

遍历

  int myints[] = {75,23,65,42,13};  std::set<int> myset (myints,myints+5); //13, 23, 42, 65, 75  for (std::set<int>::iterator it=myset.begin(); it!=myset.end(); ++it){    std::cout << ' ' << *it;  }

stack

top

  std::stack<int> mystack;  mystack.push(10);  mystack.push(20);  mystack.top() -= 5; //mystack.top() 的值为20

push

  std::stack<int> mystack;  for (int i=0; i<5; ++i) mystack.push(i);

pop

弹出栈的最上面

swap

  std::stack<int> foo,bar;  foo.push (10); foo.push(20); foo.push(30);  bar.push (111); bar.push(222);  // 执行前: foo [10, 20, 30]  //        bar [111, 222]  foo.swap(bar);  // 执行后: foo [111, 222]  //        bar [10, 20, 30]

遍历

  std::cout << "Popping out elements...";  while (!mystack.empty())  {     std::cout << ' ' << mystack.top();     mystack.pop();  }  std::cout << '\n';

map

c++ 中的map是默认按照key的排序。所以每次插入都会做调整。

insert

  std::map<char,int> mymap;  // first insert function version (single parameter):  mymap.insert ( std::pair<char,int>('a',100) );

erase

  std::map<char,int> mymap;  std::map<char,int>::iterator it;  // insert some values:  mymap['a']=10;  mymap['b']=20;  mymap['c']=30;  mymap['d']=40;  mymap['e']=50;  mymap['f']=60;  it=mymap.find('b');  //执行前: a->10, b->20, c->30, d->40, e->50, f->60  mymap.erase (it);                   // erasing by iterator  //执行后: a->10, c->30, d->40, e->50, f->60  //执行前: a->10, c->30, d->40, e->50, f->60  mymap.erase ('c');                  // erasing by key  //执行后: a->10, d->40, e->50, f->60    it=mymap.find ('e');  //执行前: a->10, d->40, e->50, f->60  mymap.erase ( it, mymap.end() );    // erasing by range  //执行后: a->10, d->40

swap

  std::map<char,int> foo,bar;  foo['x']=100;  foo['y']=200;  bar['a']=11;  bar['b']=22;  bar['c']=33;  // 执行前: foo [x->100, y->200]  //        bar [a->11, b->22, c->33]  foo.swap(bar);  // 执行前: foo [a->11, b->22, c->33]  //        bar [x->100, y->200]

遍历

for (std::map<char,int>::iterator it=foo.begin(); it!=foo.end(); ++it) {    std::cout << it->first << " => " << it->second << '\n';}

queue

push

  std::queue<int> myqueue;  myqueue.push (myint);

pop

弹出最后一个数。

swap

  std::queue<int> foo,bar;  foo.push (10); foo.push(20); foo.push(30);  bar.push (111); bar.push(222);  // 执行前: foo[10, 20, 30]  //        bar[111, 222]  foo.swap(bar);  // 执行后: foo[111, 222]  //        bar[10, 20, 30]

back

队列的最后一位

  myqueue.push(12);  myqueue.push(75);   // this is now the back  //执行前: 12, 75  myqueue.back() -= myqueue.front();  //执行后: 12, 63

front

队列的队首

  myqueue.push(77);  myqueue.push(16);  //执行前: 77, 16  myqueue.front() -= myqueue.back();    // 77-16=61  //执行后: 61, 16

遍历

  std::cout << "myqueue contains: ";  while (!myqueue.empty())  {    std::cout << ' ' << myqueue.front();    myqueue.pop();  }

deque

双向队列

front

返回队首

  std::deque<int> mydeque;  mydeque.push_front(77);  mydeque.push_back(20);  //执行前: 77, 20  mydeque.front() -= mydeque.back();  //执行后: 57, 20

back

双向队列的尾部

  std::deque<int> mydeque;  mydeque.push_back(10);  while (mydeque.back() != 0)    mydeque.push_back ( mydeque.back() -1 );

push_back

  std::deque<int> mydeque;  //执行前: []  mydeque.push_back(1);  //执行后: [1]    //执行前: [1]  mydeque.push_back(2);  //执行后: [1,2]

push_front

  std::deque<int> mydeque (2,100);     // two ints with a value of 100  //执行前: 100, 100  mydeque.push_front (200);  //执行后: 200, 100, 100    //执行前: 200, 100, 100  mydeque.push_front (300);  //执行前: 300, 200, 100, 100

pop_back

  //执行前:   mydeque.push_back (10);  mydeque.push_back (20);  mydeque.push_back (30);  //执行后: 10, 20, 30    //执行前: 10, 20, 30  mydeque.pop_back();   //执行后: 10, 20

pop_front

  //执行前:   mydeque.push_back (100);  mydeque.push_back (200);  mydeque.push_back (300);  //执行后: 100, 200, 300    //执行前: 100, 200, 300  mydeque.pop_front();  //执行后: 200, 300

insert

  std::deque<int> mydeque;  // set some initial values:  for (int i=1; i<6; i++) mydeque.push_back(i); // 1 2 3 4 5  std::deque<int>::iterator it = mydeque.begin();  ++it;    //执行前: 1, 2, 3, 4, 5  it = mydeque.insert (it,10);   //执行后: 1, 10, 2, 3, 4, 5  // "it" now points to the newly inserted 10  //执行前: 1, 10, 2, 3, 4, 5  mydeque.insert (it,2,20);                     // 1 20 20 10 2 3 4 5  //执行后: 1, 20, 20, 10, 2, 3, 4, 5  // "it" no longer valid!  it = mydeque.begin()+2;  //执行前: 1, 20, 20, 10, 2, 3, 4, 5  std::vector<int> myvector (2,30);  mydeque.insert (it,myvector.begin(),myvector.end());  //执行后: 1, 20, 30, 30, 20, 10, 2, 3, 4, 5

erase

  // set some values (from 1 to 10)  for (int i=1; i<=10; i++) mydeque.push_back(i);  // erase the 6th element  //执行前: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10  mydeque.erase (mydeque.begin()+5);  //执行后: 1, 2, 3, 4, 5, 7, 8, 9, 10    // erase the first 3 elements:  //执行前: 1, 2, 3, 4, 5, 7, 8, 9, 10  mydeque.erase (mydeque.begin(),mydeque.begin()+3);  //执行后: 4, 5, 7, 8, 9, 10

swap

  unsigned int i;  std::deque<int> foo (3,100);   // three ints with a value of 100  std::deque<int> bar (5,200);   // five ints with a value of 200    //执行前: foo [100, 100, 100]  //       bar [200, 200, 200, 200, 200]  foo.swap(bar);  //执行后: foo [200, 200, 200, 200, 200]  //       bar [100, 100, 100]

遍历

for (std::deque<int>::iterator it = mydeque.begin(); it!=mydeque.end(); ++it) {  std::cout << ' ' << *it;}

  while (!mydeque.empty()) {    sum+=mydeque.back();    mydeque.pop_back();   }

algorithm

find

  //数组中查询  int myints[] = { 10, 20, 30, 40 };  int * p;  p = std::find (myints, myints+4, 30);  if (p != myints+4)    //输出: 30  else    std::cout << "Element not found in myints\n";  // vector中查询  std::vector<int> myvector (myints,myints+4);  std::vector<int>::iterator it;  it = find (myvector.begin(), myvector.end(), 30);  if (it != myvector.end())    //输出: 30  else    std::cout << "Element not found in myvector\n";

copy

  int myints[]={10,20,30,40,50,60,70};  std::vector<int> myvector (7);  //执行前: myvector:   std::copy ( myints, myints+7, myvector.begin() );  //执行前: myvector: 10, 20, 30, 40, 50, 60, 70

swap

  int x=10, y=20;                              // x:10 y:20  //执行前: x:10, y:20  std::swap(x,y);                              // x:20 y:10  //执行后: x:20, y:10  std::vector<int> foo (4,x), bar (6,y);       // foo:4x20 bar:6x10    //执行前: foo[20, 20, 20, 20]  //       bar[10, 10, 10, 10]  std::swap(foo,bar);                          // foo:6x10 bar:4x20  //执行前: foo[20, 20, 20, 20]  //       bar[10, 10, 10, 10]

count

  int myints[] = {10,20,30,30,20,10,10,20};   // 8 elements  //记录数组myints中，10的个数  int mycount = std::count (myints, myints+8, 10);  //输出结果 mycount = 3  std::vector<int> myvector (myints, myints+8);  //记录数组myvector中，20的个数  mycount = std::count (myvector.begin(), myvector.end(), 20);  //记录数组myvector中，20的个数

replace

int myints[] = { 10, 20, 30, 30, 20, 10, 10, 20 };//执行前: myvector: []std::vector<int> myvector (myints, myints+8);            //执行后: myvector: 10, 20, 30, 30, 20, 10, 10, 20//执行前: myvector: 10, 20, 30, 30, 20, 10, 10, 20std::replace (myvector.begin(), myvector.end(), 20, 99); //执行前: myvector: 10, 99, 30, 30, 99, 10, 10, 99

fill

//执行前 myvector: []std::vector<int> myvector (8);                      //执行后 myvector: 0,0,0,0,0,0,0,0//执行前 myvector: 0,0,0,0,0,0,0,0std::fill (myvector.begin(),myvector.begin()+4,5);   //执行后 myvector: 5,5,5,5,0,0,0,0//执行后 myvector: 5,5,5,5,0,0,0,0  std::fill (myvector.begin()+3,myvector.end()-2,8); //执行后 myvector: 5,5,5,8,8,8,0,0

reverse

std::vector<int> myvector;for (int i=1; i<10; ++i) myvector.push_back(i);   // 1 2 3 4 5 6 7 8 9//执行前: 1,2,3,4,5,6,7,8,9std::reverse(myvector.begin(),myvector.end());    // 9 8 7 6 5 4 3 2 1//执行后: 9,8,7,6,5,4,3,2,1

sort

//升序bool myfunction (int i,int j) { return (i<j); }//升序struct myclass {  bool operator() (int i,int j) { return (i<j);}} myobject;int main () {  int myints[] = {32,71,12,45,26,80,53,33};  //执行前: myvector: []  std::vector<int> myvector (myints, myints+8);               //执行后: myvector: 32,71,12,45,26,80,53,33    //缺省的排序是升序(<)  //执行前: 32,71,12,45,26,80,53,33  std::sort (myvector.begin(), myvector.begin()+4);            //执行后: 12,32,45,71,26,80,53,33  //执行前: 12,32,45,71,26,80,53,33 using function as comp  std::sort (myvector.begin()+4, myvector.end(), myfunction);   //执行后: 12,32,45,71,26,33,53,80  // using object as comp  //执行后: 12,32,45,71,26,33,53,80  std::sort (myvector.begin(), myvector.end(), myobject);     //执行后: 12,26,32,33,45,53,71,80}

merge

将两个有序的组合sort1[], sort2[]。归并成一个新的有序组合。

  int first[] = {5,10,15,20,25};  int second[] = {50,40,30,20,10};  std::vector<int> v(10);  std::sort (first,first+5);  std::sort (second,second+5);  //执行前: first: 5,10,15,20,25  //       second: 10,20,30,40,50  //       v:[]  std::merge (first,first+5,second,second+5,v.begin());  //执行后: first: 5,10,15,20,25  //       second: 10,20,30,40,50  //       v:5,10,10,15,20,20,25,30,40,50

min

  //输出: 1  std::cout << "min(1,2)==" << std::min(1,2) << '\n'    //输出: 1  std::cout << "min(2,1)==" << std::min(2,1) << '\n';  //输出: 'a'  std::cout << "min('a','z')==" << std::min('a','z') << '\n';  //输出: 2.72  std::cout << "min(3.14,2.72)==" << std::min(3.14,2.72) << '\n';

max

  //输出: 2  std::cout << "max(1,2)==" << std::max(1,2) << '\n'    //输出: 2  std::cout << "max(2,1)==" << std::max(2,1) << '\n';  //输出: 'z'  std::cout << "max('a','z')==" << std::max('a','z') << '\n';  //输出: 3.14  std::cout << "max(3.14,2.72)==" << std::max(3.14,2.72) << '\n';

二分查找

lower_bound(val), 返回容器中第一个值 >= val的元素的iterator位置

upper_bound(val): 返回容器中第一个值 > val的元素的iterator位置。

堆排序

std::make_heap将[start, end)范围进行堆排序，默认使用less<int>, 即最大元素放在第一个。std::pop_heap将front（即第一个最大元素）移动到end的前部，同时将剩下的元素重新构造成(堆排序)一个新的heap。std::push_heap对刚插入的（尾部）元素做堆排序。std::sort_heap将一个堆做排序,最终成为一个有序的系列，可以看到sort_heap时，必须先是一个堆（两个特性：1、最大元素在第一个 2、添加或者删除元素以对数时间），因此必须先做一次make_heap.

//升序。左a右b，当a>b的时候，双方交换位置，bool inc_cmp(int a,int b){ return a > b; }//降序bool des_cmp(int a, int b){ return a < b; }int num[10]={3, 1, 2, 5, 6, 4};int main(){       //默认建立一个大根堆。    make_heap(num, num+6);    //小根堆: make_heap(num, num+6, inc_cmp);}

  vector<int> ivec;    for(int i=3;i<=7;++i)        ivec.push_back(i);    for(int i=5;i<=9;++i)        ivec.push_back(i);    for(int i=1;i<=4;++i)        ivec.push_back(i);    //执行前: 3,4,5,6,7,5,6,7,8,9,1,2,3,4   make_heap(ivec.begin(),ivec.end());//做最大堆排序，其实还在vector容器内    //执行后: 9,8,6,7,7,5,5,3,6,4,1,2,3,4     //执行前: 9,8,6,7,7,5,5,3,6,4,1,2,3,4   pop_heap(ivec.begin(),ivec.end());//删除最大堆，其实是把数据放到最后了！    //执行后: 8,7,6,7,4,5,5,3,6,4,1,2,3,9     //执行前: 8,7,6,7,4,5,5,3,6,4,1,2,3,9   ivec.pop_back();    //执行后: 8,7,6,7,4,5,5,3,6,4,1,2,3    //执行前: 8,7,6,7,4,5,5,3,6,4,1,2,3  pop_heap(ivec.begin(),ivec.end());//删除最大堆，其实是把数据放到最后了！  //执行后: 7,7,6,6,4,5,5,3,3,4,1,2,8   //执行前: 7,7,6,6,4,5,5,3,3,4,1,2,8   ivec.pop_back();    //执行后: 7,7,6,6,4,5,5,3,3,4,1,2   //执行前: 7,7,6,6,4,5,5,3,3,4,1,2  ivec.push_back(15);    //执行后: 7,7,6,6,4,5,5,3,3,4,1,2,15     //执行前: 7,7,6,6,4,5,5,3,3,4,1,2,15   //放入最大堆，其实是把新加入的数据，按照堆排加入堆内    push_heap(ivec.begin(),ivec.end());  //执行后: 15,7,7,6,4,6,5,3,3,4,1,2,5   //执行前: 15,7,7,6,4,6,5,3,3,4,1,2,5     sort_heap(ivec.begin(),ivec.end());//把堆排顺序，还原成一般的排序算法    //执行后: 1 2 3 3 4 4 5 5 6 6 7 7 15 

归并排序

void mergeSort(vector<int> & nums, int left, int right) {    int mid = (left + right)/2;    if(left < right) {        mergeSort(nums, left, mid);        mergeSort(nums, mid+1, right);        merge(nums, left, mid, right);    }}void merge(vector<int> & nums, int left, int mid, int right) {    if(left >= right){        return;    }    vector<int > returnNums;    int i = left, j = mid+1;    for(; i<=mid && j<=right;) {        if(nums[i] < nums[j]){            returnNums.push_back(nums[i]);            i++;        }else {            returnNums.push_back(nums[j]);            j++;        }    }    while(i<=mid) {        returnNums.push_back(nums[i]);        i++;    }     while(j<=right) {        returnNums.push_back(nums[j]);        j++;    }    for(int start = 0; start < returnNums.size();start++) {        nums[start+left] = returnNums[start];    }}

快速排序

void quickSort(vector<int> & nums, int left, int right) {    if(left > right){        return;    }    int m = quickSort0(nums, left, right);    quickSort(nums, left, m-1);    quickSort(nums, m+1, right);}int quickSort0(vector<int> & nums, int left, int right) {    cout<<"left: "<<left<<", right: "<<right<<endl;    if(left >= right) {        return left;    }    int pos = left;    while(left < right) {        while(left < right && nums[right] >= nums[pos]) {            right--;        }                if(left < right) {            swap(nums[pos], nums[right]);            pos = right;        }        while(left < right && nums[left] < nums[pos]) {            left ++;        }        if(left <  right) {            swap(nums[pos], nums[left]);            pos = left;        }    }        return pos;}